function showSubNavBrackets(id){
	document.getElementById('bracketsOpen'+id).src = './images/elements/nav_sub_open_bracket.gif';
	document.getElementById('bracketsClose'+id).src = './images/elements/nav_sub_close_bracket.gif';
}
function hiddenSubNavBrackets(id){
	document.getElementById('bracketsOpen'+id).src = './images/elements/empty.gif';
	document.getElementById('bracketsClose'+id).src = './images/elements/empty.gif';
}